#app{
  display: flex;
  align-items: center;
  background-color: #5290f9;
  min-height: 100vh;
}


.list{
  display: flex;
  justify-content: center;
  width: 100%;
}

.empty{
  height: 100px;
  width: 100px;
  border: 2px solid #333;
  background-color: #fff;
  margin-right: 10px;
}

.fill{
  width: 100%;
  height: 100%;
  background: url('https://source.unsplash.com/random/150x150') no-repeat center/cover;
}


.hold {
  border: solid 5px #ccc;
}

.empty.enter{
  border: 2px dashed #fff;
  background-color: #333;
}